The regulation says:
"Q5. What is a qualified trade or business?
A5. A qualified trade or business is any trade or business, with two exceptions:
1. Specified service trade or business (SSTB), which includes a trade or business involving the performance of services in the fields of health, law, accounting, actuarial science, performing arts, consulting, athletics, financial services, investing and investment management, trading, dealing in certain assets or any trade or business where the principal asset is the reputation or skill of one or more of its employees. This exception only applies if a taxpayer’s taxable income exceeds $315,000 for a married couple filing a joint return, or $157,500 for all other taxpayers
2. Performing services as an employee"
S-corp owners are required by law to perform services as an employee for the S-corp. Would that disqualify them for the 20% QBI deduction?